For those who wonder: 'letter_titlecase' applies to digraphs/trigraphs, where capitalization involves only the first letter. For example, there are three codepoints for the "LJ" digraph in Unicode: (*) uppercase "LJ": U+01C7 (*) titlecase "Lj": U+01C8 (*) lowercase "lj": U+01C9

For those who wonder: 'letter_titlecase' applies to digraphs/trigraphs, where capitalization involves only the first letter. For example, there are three codepoints for the "LJ" digraph in Unicode: (*) uppercase "LJ": U+01C7 (*) titlecase "Lj": U+01C8 (*) lowercase "lj": U+01C9